Some pieces of equipment, for example ink jet printers, have to be replenished with more than one fluid. For example these fluids may be an ink and a separate top-up fluid which is a solvent or carrier for the ink to adjust the viscosity of the ink during operation of the printer. The replenishment fluids are conventionally supplied in plastic bottles, metal flasks or other containers, the neck or outlet of which is secured into a corresponding socket at the inlet to the reservoir or other vessel holding the supply of that fluid for use in the equipment. For convenience the term container will be used herein to denote in general the bottle, flask, etc. in which the replenishment fluid is supplied to the equipment; and the term vessel will be used to denote the tank or other reservoir in which the fluid is stored in the equipment for use during the operation of the equipment.
The container and the vessel are often constructed so as to allow the replenishment fluid to flow from the container into the vessel once the outlet of the container has been seated home upon the inlet to the vessel, for example by having suitable engaging valve members. Where the equipment uses a number of different fluids, for example inks and solvents or different coloured inks in an ink jet printer, it is necessary to ensure that the correct container is fitted to the correct vessel to avoid contamination of one fluid with another and possible damage to the equipment, for example by feeding corrosive concentrated solvent through an ink line.
It has been proposed to colour code the cap or other closure of a container to identify the fluid contained therein and to colour code the vessels so that a user can readily see which container should be fitted to which vessel. However, this does not physically prevent the wrong container from being connected to a vessel, notably by a person who is colour blind.
It has therefore been proposed, as is acknowledged in U.S. Pat. No. 4,907,019, to form the neck of the container with a series of axial flutes which engage with axial slots formed in the inlet bore of the vessel, so that a container can only be fitted to a vessel having the corresponding slots. This provides a physical barrier to fitting the wrong container to the inlet of a vessel which does not have the corresponding slot configuration. An alternative form of such a construction is proposed in Japanese Patent Application No JP-A-61 284445 in which the inlet to the vessel has a rotatable central member which is shaped to fit into a corresponding orifice in the outlet of the container. However, such a structures require that the container outlets and the vessel inlets be especially manufactured to carry the appropriately shaped members and orifices, or flutes and slots, which adds to the cost and complexity of the equipment and restricts the freedom of a user to purchase replenishment fluids from alternative sources. Furthermore, if, as stated in the U.S. patent, a manufacturer produces a second generation of the equipment which requires a modified version of the replenishment fluid, it is necessary to structure the flutes/slots to prevent use of the first generation fluids on a second generation machine. In some cases the second generation fluids may be suitable for use in the first generation of machines, in which case it may be desirable to permit this by further permutations of the flute/slot arrangements.
The use of a flute/slot arrangement thus becomes complex and expensive and precludes alternative supply of fluids to an end user.
We have now devised a form of identification means which reduces the above problems.